LEDs based on the principle of luminescence conversion can be produced by a luminescence conversion layer applied to a radiation-emitting semiconductor chip, the luminescence conversion layer converting part of the radiation emitted by the semiconductor chip and having a first wavelength into radiation having a second wavelength, which is greater than the first wavelength. The luminescence conversion layer can contain a luminescence conversion substance, for example, which converts ultraviolet or blue light emitted by a semiconductor chip at least partly into yellow light such that white mixed light arises as a result of the superimposition of the emitted ultraviolet or blue radiation and the converted yellow radiation.
An LED based on the principle of luminescence conversion and suitable luminescence conversion substances are known from WO 97/50132, for example.
The luminescence conversion substance is typically incorporated into an organic material such as, for example, an epoxy resin or silicone, wherein the luminescence conversion layer is applied as a potting compound to the semiconductor chip.
In the case of LEDs based on the principle of luminescence conversion, an undesirable angle dependence of the color locus can occur. This is owing to the fact that radiation emitted at large angles of emergence covers a longer distance through the luminescence conversion layer and a larger proportion of the emitted ultraviolet or blue radiation is thus converted into yellow light.
A further undesirable effect for specific applications is that the luminescence conversion layer affords an undesirable yellow color impression in the switched-off state of the LED.
It could therefore be helpful to provide a radiation-emitting semiconductor component comprising a luminescence conversion layer which is distinguished by improved radiation coupling-out, improved color mixing and/or directionality of the emitted radiation.